Preparation and characterization of superhydrophobic PVDF/HMSNs hybrid membrane for CO2 absorption

Abstract Superhydrophobic polyvinylidene fluoride (PVDF) membranes were prepared via incorporated with hydrophobic modified SiO2 nanoparticles (HMSNs). Results demonstrated that HMSNs in the dope induced precipitation of PVDF, mainly by solid-liquid demixing in ethanol bath. The fabricated superhydrophobic PVDF/HMSNs hybrid membrane was showed uniformly skinless comprising of PVDF spherical microparticles. During preparation, the HMSNs attach onto the PVDF microsphere surfaces as-formed micro-nano structures, which was important for imparting membrane superhydrophobicity. Therefore, the water contact angle of PVDF/HMSNs hybrid membrane was 155° as the mass ratio of HMSNs with PVDF matrix was 0.15:1 when ethanol coagulation bath was used. Since the proposed modification allowed HMSNs migration onto PVDF spherical microparticles surfaces during the exchange between solvent and non-solvent, the hydrophobicity of internal surface of membrane pores and channels was also enhanced. This feature successfully inhibited the liquid intrusion into membrane pores, and guaranteed a stable anti-wettability over a long period. The absorption flux was 2.34 mmol m−2 s−1 for prewetted as the mass ratio of HMSNs with PVDF matrix was 0.15:1 with a fluid flow rate of 240 mL min−1, 3.3 times higher than the prewetted pristine PVDF membrane. These results show that PVDF/HMSNs hybrid membranes are ideal candidates for application in CO2 absorption.